Research On Vibration And Noise Of Gearbox In Low Floor Light Rail Vehicle

The 100% low floor light rail transit system is a new type of urban transportation,which has the advantages of low construction cost,convenient for passengers to get on and off,and urban sightseeing function.This kind of transportation system is suitable for the branch transportation of large cities and the trunk transportation of medium-sized cities.With the development of society,passengers have put forward higher requirements on the riding comfort of vehicles,which makes vehicle manufacturers pay more and more attention to the vibration and noise control performance of products.Because of its unique 100% low floor structure,the gearbox system of 100% low floor light rail transit system has the characteristics of compact structure and large load.As a core component of 100% low floor light rail vehicles,the gearbox system is one of the main sources of vehicle vibration and noise.Carrying out gearbox vibration and noise research will help improve the NVH performance of 100% low floor light rail vehicles.In this paper take a 100% low floor gearbox as the research object,comprehensively adopts rigid-flexible coupling multi-body dynamics method,finite element modal analysis and dynamic response analysis method,and acoustic boundary element method to deeply investigate its vibration and radiated noise characteristics.Using similarity theory,a similarity model of a 100% low floor gearbox housing is designed,and experimental modal analysis and computational modal analysis are performed on the similarity model.Combined with the actual design and installation of a 100% low-floor gearbox,an optimized design of radiated noise was carried out for this gearbox.The main research contents of this article are as follows:(1)A rigid flexible coupling multi-body dynamic simulation analysis model of 100% low floor gearbox is established,which considers the flexibility of the structural system and the coupling of the transmission system.The bearing reaction force obtained by simulation is used as the excitation force for the dynamic response analysis of gearbox.(2)Based on the similarity theory,a similarity model of a 100% low-floor gearbox box was designed,the similarity model and the prototype similarity criterion were derived,and a 3D printing technology was used to manufacture the housing similarity model.Carry out experimental modal analysis and computational modal analysis on the similar model,and compare and analyze the modal parameters obtained from the experiment and simulation to verify the correctness of the simulation and experiment.Carry out computational modal analysis on the prototype,and compare it with the results of similar model experimental modal analysis to verify the correctness of the housing finite element model modeling and experimental design.The reaction force of the bearing support obtained from the rigid-flexible coupling multi-body dynamics simulation is used as the excitation,and the dynamic response analysis of the housing is carried out to calculate the vibration response.(3)The radiated noise simulation analysis model of 100% low-floor gearbox direct boundary element method is established.The vibration response obtained from the dynamic response analysis of the housing is taken as the boundary condition of the simulation analysis model,and the radiation noise characteristics of the gearbox are studied.(4)According to the research and analysis results of vibration and noise of 100% low floor gearbox,combined with the actual design and installation of the gearbox,the two methods of tooth profile modification and housing structure optimization are adopted to carry out the optimization design of radiation noise of 100% low floor gearbox.